1. Field of the Invention
The present invention relates to a design support method, a design support system, and a design support program for supporting the design of a heat convection field or a mass diffusion field.
2. Description of the Related Art
Design of a heat convection field or a mass diffusion field is required in various sites or uses such as, for example, design of an indoor environment using an air conditioning apparatus, thermal design of electronic devices, and management of exhaust gas concentration in plants.
Along with the recent increase in the operation speed of computers, numerical simulations of a heat convection field or a mass diffusion field have been put into practice, and some general purpose heat and fluid flow analysis software and the like have already become commercially available and are used as designing tools. However, such software is generally used to simply obtain a solution to appropriate parameters given by a designer. For the purpose of optimization, such designing parameters are now repeatedly modified in a trial-and-error manner based on the experience of designers. Namely, the solution obtained by a numerical simulation performed once is merely a specific solution to a specific boundary condition (an initial value of a designing parameter). When the boundary condition is changed, the numerical simulation needs to be performed again.
In the meantime, an inverse problem approach which combines a numerical simulation and mathematical programming to realize automatic optimization is recently a target of attention. Various methods of optimization have been attempted. Such optimization methods are roughly classified into gradient-based optimization methods using numerical derivatives obtained by a finite difference method, and global optimization methods using genetic algorithms or the like. With each group of methods, the required number of times of numerical simulation rapidly increases as the number of designing parameters increases. Therefore, in the case where the number of designing variables is large or infinite (distribution amount), it is difficult to realize optimization within a reasonable amount of time.
Such a conventional technique of giving a boundary condition and then obtaining the temperature or the like at a target position (hereinafter, referred to as the “forward problem approach”) is not practical because the numerical simulation needs to be performed too many times until the design purpose is achieved. For these reasons, there have been no general-purpose design support systems which are easily usable at the site of design.
A technique of analyzing the influence, of a change in the temperature or the like as a boundary condition, exerted on a minute temperature change or the like of the target position to find a desirable boundary condition (hereinafter, referred to as the “inverse problem approach”) has been proposed (see, for example, non-patent documents Kazunari MOMOSE et al., “Influence of Thermal and Flow Boundary Perturbations on Convection Heat Transfer Characteristics,” Journal of The Japan Society of Mechanical Engineers (edition B), June 2000, Vol. 66, No. 646, pp. 215-221, and Kazunari MOMOSE et al., “Influence of Thermal and Flow Boundary Perturbations on Convection Heat Transfer Characteristics: Numerical Analysis Based on Adjoint Formulation”, 2002 Wiley Periodicals, Inc., Heat Transfer Asian Research, 32(1): 1-12, 2003; Published online in Wiley InterScience (WWW.interscience.Wiley.com). DOI 10.1002/htj.10065).
According to the methods described in the above non-patent documents, in order to comprehensively evaluate the influence of thermal and flow boundary perturbations, a perturbation equation from the convection field, which is used as the reference, is introduced and the adjoint formulation to the perturbation equation is derived. In accordance with the problem, an adjoint problem and the boundary condition therefore are set. Using the numerical solution in the reference state together with the numerical solution to the adjoint problem, changes in various heat transfer characteristics to an arbitrary thermal perturbation and an arbitrary flow perturbation on the boundary are estimated.